#define  _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include <stdio.h>
#include<string.h>
////int main() {
////    char arr[1001]={0};;
////    scanf("%s", arr);
////    int n = strlen(arr);
////    int i, j;
////    for (i = 0; i < n - 1; i++)
////    {
////        for (j = 0; j < n - 1; j++)
////        {
////            char h = 0;
////
////            if (arr[j] > arr[j + 1])
////                h = arr[j];
////            arr[j] = arr[j + 1];
////            arr[j + 1] = h;
////        }
////
////    }
////    printf("%s", arr);
////
////    return 0;
////}
//int main()
//{
//	int arr[2][3] = { 1,2,3,
//				      4,5,6
//	};
//
//	printf("%d", *(arr + 1));
//
//	return 0;
//}
//
//

#include <stdio.h>

int main()
{

   char  arr[500];
   char add[128];
  scanf("%s",arr);
  int i = 0;
   for (i = 0; i < strlen(arr); i++)
  {
          if (arr[i] >= 0 && arr[i] <= 127)
           add[arr[i]] = 1;

   }
   int sum = 0;
  for (i = 0; i < 128; i++)
   {
 if (add[i] == 1)
    sum++;
}
printf("%d",sum);
return 0;
}